Would changing the Diff cover affect the handbrake? *Now sorted*

[Dave Dyer]

Hi,

I put my car through an MOT yesterday, after being off the road for 20 years and worked on for the last 2 years.
Anyway it failed (I didn't think I would get it all right first time!) but the main failure was the handbrake, the drivers side on test pulled 145 kgf but the passenger side only pulled 64 kgf.

I have changed the axle diff case for the alloy type cover off an SD1 axle and when the handbrake is pulled the cable on the passenger side pulls against the cover, do you think this would affect the handbrake? does it need the cable to have a straight run.

I don't really want to put the old tin type cover back as it will be an awkward and messy job, plus the alloy cover seems stronger and seals well, to find it makes no difference. But if its the cause of the problem then I will have to.

The MOT man told me I get once chance on a retest, if its still not right I'll have to pay for a full test again!

Any help would be very welcome.

Thanks, Dave

[Hasbeen]

If you are talking about just the back cover, it has nothing to do with the brakes in any way. If the cable is rubbing hard on it, a little grease should fix it. If it is rubbing very hard something is wrong with the pivot lever, or the lever on the drum. Fix them, or install the outer sheath from a hand brake cable for the cable to run in.

Changing the axel housing may cause hand brake problem, but only because you have not set the handbrake up properly on the new one.

As you must know the handbrake depends on the pivot arm on the diff housing, & on the adjustment of the cables from it to each of the leavers on the drums.

I suggest you check the movement of that pivot arm, but more importantly the action of the leaver the drums. If that is free & applying the brake when operated by hand, it is probably just a matter of adjusting the length of the cables from the main pivot to each of the drums to get a balance between them.

Hasbeen

[Dave Dyer]

Hi Hasbeen,

I see what you are saying about the cable and axle cover, so probably not at fault, also as you said I looked at the action of the levers and the drums. I removed the drums and looked at what happens when the handbrake is pulled, there is a difference between each side, the drivers side both shoes move out a little, but on the passenger side only 1 shoe moves out, the other stays exactly where it is. But as much as I look at each side I can't see any difference, also I can't see whats happening to make the shoes move out. Its just so awkward getting my head down there and trying to see whats happening.

Dave

[FI Spyder]

Basically what Hasbeen said. The cable does lightly touch the cover on stock (see picture). If it does touch the replacement cover that's OK the friction will be negligible. If the cable is deflected by the cover you will lose some force but not that much depending how much deflection. The pivot should be clean and greased to keep any friction to a minimum and there should be no damage restricting movement. More important is the operation of the actuating levers in the drums. This is were you should concentrate your attention. The mechanism should be clean and free of old brake dust/grease/rust and contact points greased with brake grease that is formulated for this and doesn't migrate (don't use normal grease thinking it will suffice). Just a thinnest coating needed. It must be assembled correctly of course with the drums set up with final setting done by brake adjusters by driving back and forth with brisk braking so the auto adjusters can adjust the drums to optimum. This will ensure both sides are operating at optimum. Picture is before I took out axle in process of removing tank.



After cleaning and a little paint and polish.

[saabfast]

The manual has a procedure for adjusting the cable, although I still found it a bit hit & miss. The compensator has to be in the right position and then the clevis on the drum operating arms adjusted to pull evenly. Worn pivots on the drum arms can affect it. I think some extending adaptors have been made to lengthen the arms and improve the force but I found that when I rebuilt mine it was not necessary. There is also an adjustment under the handbrake lever (under the car) where it connects to the first single cable if I remember correctly. Mine is now very effective with a few clicks of the handbrake lever.

[dursleyman]

saabfast has said it pretty well, its most important to set up and adjust the individual brakes on each side first, before attempting to connect and adjust the cables. The compensator should be pretty much close to vertical with the brake off, if its not you won't get the best effect. The cables will also be fairly loose in the off position it should not be tight.
I do have a set of the extended levers on mine very kindly sent to me by Stag76 and they do improve the "bite" but these are not a substitute for a properly adjusted set up in the first place.

[sonscar]

I echo all of the above,I was told that the compensator armshould be as near vertical as possible with the brake fully on to give maximum pull.I also found that the auto adjuster did not quite fully adjust the shoes so I manually adjusted it by removing the drums and clicking it a few times.I find the handbrake good but due to my small stature I find the lever awkward to operate and have failed to release it fully on many occasions despite the warning light glowing.Must learn to drive someday,Steve..

[Dave Dyer]

Thanks Chaps for your replies.

I checked the linkages inside the drum, stripping it all down as well, I lubricated the pivots and its now better, but still not as good as the other side.
I have the compensator slightly to the left and have adjusted to give about 7 clicks on the handbrake, not sure how many I am allowed.
With the handbrake pulled and with a bar on the drum I can't turn the drivers side (sorry should really say right hand side!) but with a bit of effort I can move the left side drum.

Would a new set of brake shoes help? these aren't new, a bit of wear, not too bad, but were on the car when I took it off the road 20 years ago, so I just reused them.

Dave

[Rich K]

Hi Dave,
I recently went through the steps described to set up the brakes for MOT on a car I have been restoring. Once everything had been cleaned up and the pivots lubricated with copper grease I adjusted the hand brake to give between 5 and 7 clicks. Like you I found that one wheel could be turned slightly with moderate force. I then adjusted the cable fork end to tighten the cable tension slightly on that side. If you have the rear of the car jacked up off the ground you can check when the brakes on either side just start to bind in response to pulling the hand brake lever up and thus get the balance right. It worked for me as the car flew through the MOT test. Hope this is helpful, Rich.

[Hasbeen]

As rich says above.

One other thing, which may help just for your MOT would be to lightly sand the shoes to break any glazed surface.

It may also help to remove any glaze from the drum, by hand, or getting them lightly skimmed, if there is still anyone near by who still does it.

Either would be a very short term improvement of handbrake effect, but may just tip the result enough to pass.

Hasbeen

[john 215]

Hi Dave,

Never had an issue when I was running drums and a alloy cover.

Make sure the pivot is free just after it enters the drum, terrible for seizing and / or getting tight. Other than that, as all the checks the other learned gentlemen have said.

Cheers John

[Ianftr8]

Dave,

You should be able to get the passenger side to pull up better by just adjusting up the short cable at the drum end by tightening it using the ten mm nuts where the clevis pin fits.

Worth making sure they are clean and have some grease to keep them free.

Cheers
Ian

[Dave Dyer]

Thanks Chaps for the advice.

I fitted new brake shoes to the weak side (passenger/left side) and checked all pivots and greased them and set the handbrake for 6 clicks but I can still move the drum under force.
I cleaned the brake drum with fine emery and lubricated the compensator lever, it made a slight improvement, but I could still move the drum.

I also tried adusting the cable at the drum on the passenger side, but it just reduced the amount of clicks on the handbrake. The compensator arm moved as I adjusted it, I think thats how it works. It seems you can't adjust just one side, it seems to (via the compensator arm) divide the adjustment to both sides keeping both sides equal.

I'm running out of ideas and the re-test is booked for this Friday! I'm not sure what else I can do next?

Thanks, Dave

[Dave Dyer]

Hi Chaps,
I had a good think about the hand brake set up and can see the right hand side brake is a direct pull from the hand brake cable, where the left hand side relies on the movement (and possible drag) of the compensator lever. The bushes are new in the compensator lever but it still looks like its twisting very slightly in operation. The bushes would be better if they were more solid, say made out of nylon plastic. Anyway it all adds up to the left side not working as well.

So after sleeping on it, it suddenly came to me, a solution. I made an extension braket that bolts on to the lever at the brake drum, I put 3 spaced holes in it to attach the hand brake cable. I started with the first hole (nearest the original hole) so about 2cm more leverage, tried the hand brake and it now pulls correctly on both sides. It just needed that extra 'pull' on the left hand side, I'm a happy man again!

Cheers,
Dave

[FI Spyder]

Ingenious mod. If the compensator arm was twisting due to deflection of replaced bushes (or wear) it could easily be losing some of the force needed. hard nylon bushes might well have worked (as well as maybe new arm) but if it works and stands up to forces on it, well done.